1. Field of the Invention
The present invention relates to an automotive climate control system or, in particular, to an automotive climate control system using carbon dioxide or a hydrocarbon compound (combustible refrigerant) such as propane as a refrigerant.
2. Description of the Related Art
In the invention of an automotive climate control system using a combustible refrigerant such as propane disclosed in Japanese Unexamined Patent Publication (Kokai) No. 9-11734, whether the refrigerant is leaking or not is detected by a sensor and, in the case where a refrigerant leakage is detected, an electric actuator such as a servo motor is activated to open an external air inlet to introduce air from outside the cabin thereby to prevent the leaking refrigerant from flowing into the cabin.
With the aforementioned invention, however, as long as the vehicle is stationary with the ignition switch off, power cannot be supplied to the sensor and the electric actuator. In the case where the refrigerant leaks out while the vehicle is stationary, therefore, action against it cannot be taken.
This inconvenience may be obviated by providing means for supplying power constantly to the sensor and the electric actuator at the sacrifice of an increased power load on the battery.
In view of the aforementioned fact, the object of the present invention is to provide an automotive climate control system, in which the refrigerant which may leak out is prevented from flowing into the cabin even in the case where the electric equipment on board the vehicle is not supplied with power such as when the ignition switch is in off state.
In order to achieve the above-mentioned object, according to a first aspect of the invention, there is provided an automotive climate control system comprising an air-conditioning casing (11) which allows air to flow therethrough and to be blown out into the cabin, a first heat exchanger (12) arranged in the air-conditioning casing (11) for exchanging heat between the refrigerant and the air, a face opening (17) arranged downstream of the first heat exchanger (12) in the air flow for blowing out the air to the faces of the occupants in the cabin, a foot opening (18) arranged downstream of the first heat exchanger (12) in the air flow for blowing out the air to the feet of the occupants in the cabin, a defroster opening (19) arranged downstream of the first heat exchanger (12) for blowing out the air to the vehicle windshield glass, an internal air inlet (22) arranged upstream of the first heat exchanger (12) in the air flow for introducing the air from the cabin, and an external air inlet (23) arranged upstream of the first heat exchanger (12) for introducing the air from outside the cabin wherein, as long as the electrical equipment mounted on the vehicle is not supplied with power, among a first air path (A) leading from the first heat exchanger (12) to the face opening (17), a second air path (B) leading from the first heat exchanger (12) to the foot opening (18) and a third air path (C) leading from the first heat exchanger (12) to the defroster opening (19), only the air path (C) having a larger air resistance than an air path (E) leading from the first heat exchanger (12) to the external air inlet (23) passes the air therethrough while, at the same time, the air passes through the air path (E) leading from the first heat exchanger (12) to the external air inlet (23).
As a result, the refrigerant which may leak out from the first heat exchanger (12) can be passed to the external air inlet (23). Thus, the refrigerant that may leak from the first heat exchanger (12) while the ignition switch is in off state can be prevented by simple means from flowing into the cabin without any leakage protection device such as a sensor.
According to a second aspect of the invention, there is provided an automotive climate control system comprising an air-conditioning casing (11) which allows air to flow therethrough and to be blown into the cabin, a first heat exchanger (12) arranged in the air-conditioning casing (11) for exchanging heat between the refrigerant and the air, a face opening (17) arranged downstream of the first heat exchanger (12) in the air flow for blowing out the air to the faces of the occupants in the cabin, a foot opening (18) arranged downstream of the first heat exchanger (12) in the air flow for blowing out the air to the feet of the occupants in the cabin, a defroster opening (19) arranged downstream of the first heat exchanger (12) for blowing out the air to the vehicle windshield glass, an internal air inlet (22) arranged upstream of the first heat exchanger (12) in the air flow for introducing the air from the cabin, and an external air inlet (23) arranged upstream of the first heat exchanger (12) for introducing the air from outside the cabin wherein, as long as the electrical equipment on board the vehicle is not supplied with power, among a first air path (A) leading from the first heat exchanger (12) to the face opening (17), a second air path (B) leading from the first heat exchanger (12) to the foot opening (18), a third air path (C) leading from the first heat exchanger (12) to the defroster opening (19), only the air path (C) having the largest air resistance passes the air while, at the same time, the air passes through the air path (E) leading from the first heat exchanger (12) to the external air inlet (23).
As a result, as in the first aspect of the invention, the refrigerant that has leaked out can be prevented from flowing into the cabin with simple means without any protective device such as a sensor.
According to a third aspect of the invention, there is provided an automotive climate control system comprising an air-conditioning casing (11) which allows the air to flow therethrough and to be blown into the cabin, a first heat exchanger (12) arranged in the air-conditioning casing (11) for exchanging heat between the refrigerant and the air, a face opening (17) arranged downstream of the first heat exchanger (12) in the air flow for blowing our the air to the faces of the occupants in the cabin, a foot opening (18) arranged downstream of the first heat exchanger (12) in the air flow for blowing out the air to the feet of the occupants in the cabin, a defroster opening (19) arranged downstream of the first heat exchanger (12) for blowing out the air to the vehicle windshield glass, an internal air inlet (22) arranged upstream of the first heat exchanger (12) in the air flow for introducing the air from the cabin, and an external air inlet (23) arranged upstream of the first heat exchanger (12) for introducing the air from outside the cabin wherein, as long as the electrical equipment on board the vehicle is not supplied with power, the air path (C) leading from the first heat exchanger (12) to the defroster opening (19) passes air while at the same time passing the air through the air path (E) leading from the first heat exchanger (12) to the external air inlet (23).
As a result, as in the first embodiment of the invention, the refrigerant that has leaked out can be prevented from flowing into the cabin by simple means without providing any protective device such as a sensor.
According to a sixth aspect of the invention, there is provided an automotive climate control system wherein a second heat exchanger (13) for heating the air is arranged between the first heat exchanger (12) and the three openings (17 to 19) in the air-conditioning casing (11), and as long as the electrical equipment mounted on the vehicle is not supplied with power, the air flowing from the first heat exchanger (12) toward the second heat exchanger (13) passes in its entirety through the second heat exchanger (13).
As a result, the air resistance in the air path in the openings (17 to 19) can be further increased, so that the refrigerant that has leaked out from the first heat exchanger (12) can be positively passed to the external air inlet (23). Thus, the refrigerant can be prevented without fail from flowing into the cabin.
According to a seventh aspect of the invention, there is provided an automotive climate control system, comprising an air-conditioning casing (11) having arranged therein a second heat exchanger (13) between a first heat exchanger (12) and three openings (17 to 19) for heating the air, a bypass (14) for causing the air passing from the first heat exchanger (12) toward the second heat exchanger (13) to bypass the second heat exchanger (13) and a bypass amount regulation means (15) for regulating the air passage in the bypass (14), wherein the bypass amount regulation means (15) closes the bypass (14) as long as the electrical equipment mounted on the vehicle is not supplied with power.
As a result, the air resistance in the air path in the openings (17 to 19) can be further increased, so that the refrigerant that has leaked out from the first heat exchanger (12) can be positively made to flow to the external air inlet (23). Thus the refrigerant can be prevented without fail from flowing into the cabin.
According to an eighth aspect of the invention, there is provided an automotive climate control system, wherein a fluid having a higher density than air is used as a refrigerant, and the external air inlet (23) is arranged at a position lower than the defroster opening (19).
As a result, the refrigerant heavier than air which may leak out little by little from the first heat exchanger (12) when the ignition switch is in off state, for example, can be discharged out of the cabin from the external air inlet (23) earlier than from the openings (17 to 19) inside the cabin, and therefore the refrigerant can be prevented from flowing into the cabin more positively.
The present invention may be more fully understood from the description of preferred embodiments of the invention set forth below, together with the accompanying drawings.